extruder fan not cooling

I've done a couple of prints but never finished any of them because the plastic melts up in to the the extruder motor and doesn't feed throw the nozzle and I've noticed that the fan doesn't run. Any help would be appreciated

I don't know if you're facing a similar issue, but this happened to me on larger prints for slic3r, since the layer takes long enough to print that it should cool before starting the next, so it doesn't turn on the fan. You can change settings in slic3r to always have fan on in expert mode.

I went through the same issues for a short while after building mine.I saw print failures left and right and started cussing over the extruder design. But then I noticed the fan would not start at all.What I started to notice was that the fan just simply would not spin up. With some help maybe, but it would eventually quit mid-print.

I ended up replacing my fan with a new one and it(the fan) has been running fine ever since.

Since you have already replaced yours, I cannot help any further other than to suggest you trace your connections all the way back to the mainboard.